Purification of turpentine



Patented Nov. 16, 1948 UNITED STATES PATENT OFFICE 2,453,712 PURIFICATION OF 'I'URPENTINE Milton P. Kleinholz, East Chicago, Ind., assignor to Sinclair Refining Company, New York, N. Y., a corporation of Maine. I

No Drawing. Application June Serial N0. 674,932

2 Claims. (Cl. 260675.5)

My invention relates to oxygen compounds from turpentine, by which term I mean to embrace not only turpentine itself, but also turpentine fractions, including turpentine oil and the material sold under the name Pinene 111, which is a fractionated turpentine reported as containing about 92% alpha pinene, 45% camphene, and 34% dipentene and other terpenes.

Copending application, Serial No. 494,687 of Robert L. May, filed July 14, 1943, describes a phosphorusand sulfur-containing addend for mineral and lubricating oils, which is obtained a method for removing patents Nos. 2,392,252 and 2,392,253, both of which issued on January 1, addends produced by further reacting the phosphorus sulfide-turpentine reaction product or a substance derived therefrom with other materials.

applications, above identified, not noticeable in the addend itself but develops following addition of the addend to the lubricating oil.

According to the present invention, I remove or inactivate a substantial portion of these oxygen compounds before the turpentine is reacted with the phosphorus sulfide and I thereby materially improve the odor of compounded oils conprocess, I have found that the sodium alcoholates are, in general, more effective than the potassium alcoholates and I have obtained particularly good results with sodium methylate.

I am not certain as to the mechanism of the reaction involved in my process but it appears that the metal of the alcoholate causes the poly- 1946, describe merlzation of the oxygen impurities or that metal derivatives of the oxygen impuritie are formed which do not react with phosphorus sulfides.

In the practice of my process, I generally heat the mixture of turpentine and alcoholate to reboiling range or, product, the clear liquid obtainable by filtration and decantation of the residue following a distillation carried out at a temperature up to the boiling range of the product.

The following examples submitted in illustration of my invention are not to be construed as in any way restrictive of the scope thereof:

Example 1 In a blank test, a sample of pinene 111, 544 grams, (4 moles), was heated on a sand bath in a three liter, three-necked flask equipped with a mechanical stirrer. After the temperature reached 250 F. the source of heat was removed of phosphorus pentasulcontinued for 12 hours at 275 F., following which 176 grams, 1 mole, of p-cyclohexylphenol was added. After further reaction for 10 hours at 275 F., the mixture was blended with 1022 grams of a low viscosity mid-continent oil. 2% parts by weight of the resulting oil concentrate, after filtration, was mixed with 97 7 parts by weight of a mid-continent SAE 20 motor oil. This blend had an offensive onion-like odor suggestive of mercaptans.

Example 2 A second sample of the pinene 111 was distilled and 544 grams of the overhead (boiling at blend was equivalent to that of of Example 1.

the final blend Example 3 A 1400 gram sample of pinene 111, from the same shipment as the pinene 111 employed in Examples 1 and 2, was refluxed for about 1 hour with 233 firams of sodium methylate powder, following which the mixture was subjected to a distillation in which a fraction boiling at 156-157 C. was taken as the product. Employed in the procedure of Example 2, this product gave a blend which was nearly odorless.

Example 4 19.5 grams of metallic potassium was dissolved in 150 cc. anhydrous methanol and the solution added to 1000 grams of the pinene 111. The excess alcohol was distilled off and the residual liquid refluxed for about 1 hour and distilled. A portion of the distillate boiling at l5615'l C. was employed in the procedure of Example 2. The odor of the final blend was much less offensive than that of the final blend in the case of either Example 1 or Example 2.

Example 5 A kilogram of the pinene 111 was refluxed for 1 hour with 30 grams sodium methylate (powder). The mixture was then distilled to separate materials boiling below 155 C., and the residue cooled and filtered. A small volume of heavy liquid in the filtrate was separated by decantation and the remaining liquid refiltered until clear. A portion of the final filtrate employed in the procedure of Example 2 gave a blend having an odor equivalent to that of the blend of Example 4.

Apart from the fact that it improves the odor of the blends, my process is advantageous in that the addend is rendered more thermally stable. Thus, when the phosphorus sulfide-turpentine reaction product, prepared with turpentine which has been treated according to my process, is heated under reflux at 350 F. for as long as 16 hours, no decomposition, as would be indicated by the formation of a precipitate, occurs. On the other hand, when the reaction product is prepared, as heretofore, With turpentine from which Number oxygen impurities have not been removed, a pre--' cipitate is formed intwo hours and the precipitate progressively increases in quantity on further heating.

Where the turpentine to be processed according to my invention has a high peroxide content, it is advantageous to subject it to a pretreatment with caustic soda or other alkali in order to reduce alcoholate consumption. Contrary to what might be expected, the alkali treatment alone will not remove oxygen compounds responsible for the objectionable odor in the blends.

After purification according to the invention an oxidation inhibitor, such as hydroquinone or pyrogallol may be added to the turpentine in order to prevent the subsequent formation of oxygen impurities.

I claim:

1. A process which comprises heating turpentine with an alcoholate from the group consisting of sodium and potassium alcoholates to remove or inactivate oxygen impurities contained in the turpentine.

2. A process which comprises refluxing a turpentine fraction containing a predominant proportion of alpha-pinene with sodium methylate to remove or inactivate oxygen impurities present in the fraction.

MILTON P. KLEINl-IOLZ.

REFERENCES CITED UNITED STATES PATENTS Name Date Sherk Sept. 14, 1926 FOREIGN PATENTS Country Date Great Britain 1906 Germany Aug. 20, 1926 Number 

